Jessica Ennis Hill, Dame Jessica Ennis Hill, believes she could have been a better athlete if she had worked around her periods.

Nearly 10 years ago, Jennis, a women's-cycle mapping app, was awarded gold in the London Olympics heptathlon.

It will help users to make the most of their hormones by showing them how to exercise in different ways at different times throughout the month.

Experts say that every woman experiences the menstrual cycle in a different way.

Dame Jessica recalled starting her period at the Junior European Championships, Lithuania in 2005.

She said, "I was so preoccupied that anyone would see that I had started my period and that it wasn't protected."

"I can remember running the 800m thinking that I was trying to win a gold medal, but I also know that I just started my period.

"I rushed off the track, and I felt like I couldn't absorb that incredible, gold-medal moment.

"That was something that really stood out to me as an Olympic athlete."

Experts say period tracking is something anyone can use, not only professional athletes. There are many popular apps available, such as FitrWoman and Clue, along with Flo.

The cycle lasts for most people around 28 days. There are four phases during which the main sex hormones, progesterone and oestrogen, fluctuate and produce varying amounts of energy.

"Maybe, if I had spent more time understanding, especially when to push myself into the strength room during that follicular stage, then maybe I would've built more lean muscle, and become stronger," Dame Jessica said to BBC News.

"Who knows? It may have had a positive impact on my performance."

Kelly Lee McNulty at Northumbria University is still studying the effect of menstrual cycles on exercise. However, she said that more research is needed.

She said, "At this moment, the research in the field is still in its infancy."

"Only 6% have focused on women in sport and exercise research."

"That shows the gaps in our knowledge about women's specific factors.

"There are four major studies on periods and exercise. They were all done in the 1990s. None of them used blood sampling or gold-standard methods.

"We must move forward. Not only should we increase the amount of research that we get, but also we need to improve it so we can draw more precise conclusions about female physiology."

There are many factors that can affect menstruation, including obesity and stress. Ms McNulty cautioned against giving "one-size fits all" advice.

She said, "Women are on the spectrum."

Some won't notice or get any benefits, while others will notice huge differences in their performance.

"It's all about being aware and in control of your individual physiology."

Dawn Scott, the head coach of the US women's football team, stated that tailoring diets and exercising around periods helps optimise performance.

Some people find periods taboo.

"I remember it being awkward conversation," said Dame Jessica.

"I had a male coach, and it was predominantly male.

"I can remember small conversations like, 'I'm having my period or I'm tired' or 'I'm not feeling 100%'. But I never felt confident enough to have an open discussion about how I felt about training and how it made me feel.

"That was something that was still very much taboo, and something that we didn’t really focus on unless that was having a negative effect on my training."

Sarah Taylor, 45, has been using Jennis for several months after entering the perimenopause.

"I was shocked at how little information is available about women's health.

"It seems taboo to speak about periods, especially the perimenopause.

"The dialogue is changing though, and I want to be a part of it."

According to the Jennis team, the app will be more tailored the more data it receives. It will also work for people with irregular cycles if there is more data.

"It's certainly in its early stages – but we want to reach maximum number of women and help them understand hormones and their bodies," said Dame Jessica.

Follow Shiona McCallum @shionamc